Understanding Micron Ratings: How Fine Should Your Water Filter Be?

Wow, there is more to this water purity business than meets the eye, right? You’re suddenly in a world of technical terms, and here is another one: micron ratings. What on earth are they, and how do they affect your choice of water filter?

What are Microns?

Anything that contains the letters micro refers to something extremely small. In this case, we’re looking at impurities in water, including those so small we can’t see them. A micron (AKA micrometer) is a unit of measurement, one millionth of a meter.

What we filter out of water starts with the bigger stuff. If water is muddy or cloudy, that means dirt of one color or another, and we can tell when we’ve got rid of it because we can’t see it anymore. A five or 10-micron filter is usually enough for this, and of course, we feel better when the water is clear, because that suggests it is clean. We’ve got rid of the sediment, silt, mold, and so on that make the water visually unattractive, and humans have learned through bitter experience down the millennia, if it looks dirty, it is probably harmful in some way.

But there are degrees of cleanness that we can’t see with the naked eye, and that’s when the micron ratings get really small. To deal with bacteria, we’re looking at a micron rating of 0.2 – 1 micron. In a water filter, the micron rating is the size of the pores, the microscopic holes that let water through and keep anything else out.

Filters are basically materials containing tiny pores that do the same job as shrimping nets, which let the water through but keep the shrimp along with pebbles and visible seaweed (although there will be tiny fragments of seaweed in the water that escapes). But that’s what makes nets different from filters: it’s what remains in the net that we’re interested in, while with a filter, we’re just happy the extraneous matter has gone, so we can use the water. Fly screens are another example: the air goes through them, but the mosquitoes don’t. No offence, bugs of the world, but you belong outside, not in the house, just as we want the pure water without the material that can spoil it.

What Kinds of Filters Have Micron Ratings?

Sediment filters are obvious examples, but micron ratings apply to carbon filters too. There are various types of sediment filters, each with a descriptive name, but it is the size, not the style, that concerns us here.

A micron rating of 50 or 25 will remove most visible grit, sand, and mud particles, but will do nothing against the smaller material, which can be responsible for infections and the spread of diseases and viruses.

A one-micron filter can remove E. coli and salmonella, to name just two of the better-known things we don’t want anywhere near our water.

What Micron Rating Do I Need in My Area?

This is a good question, because what you need as regards water purification depends on where you live and what the water is like around there. Even municipal water, which has been treated by your local water department, will contain tiny amounts of things it shouldn’t in a perfect world. That variation from place to place means there is no single minimum micron rating that will cover everyone.

The answer is that you should get your water tested, and the same water purity companies that do the testing will often supply the water filtration system too, so a couple of phone calls to reputable firms can get you on track for beautiful water that is absolutely safe.